Gas turbines play a predominate role in a number of applications, namely in aircraft propulsion, marine propulsion, power generation, and driving processes such as pumps and compressors. Typically, a gas turbine includes a compressor, a combustor, and a turbine. In operation, air is fed into the system where it is compressed by a compressor and further mixed with fuel. The compressed air and fuel mixture are then burned to cause an expansion, which is responsible for driving the turbine. Thus, gas turbines require large quantities of air to create the torque driving the turbine. A typical gas turbine may devote up to 65% of its available energy to compress the air being fed into the turbine. Consequently, any loss in compressor effectiveness will cause degradation and a significant loss in lost performance.
Due to the large quantities of air utilized by the turbines, a large amount of airborne contaminates, pollen, insects, and dust just to name a few, are fed into the compressor. Thus, an issue arises wherein contaminates or foreign particles, commonly referred to as fouling, collect and build up in the turbine, particularly in the compressor. Fouling of the compressor reduces the compressor efficiency. Reduced compressor efficiency means that the compressor requires more power for compressing the same amount of air. As a result, the power required for driving the compressor increases and thus, the surplus power decreases, meaning less available power to drive the turbine. Furthermore, a decrease in available power may lead to a lower overall power output. As it will be recognized by one of ordinary skill in the art, it is desirable to provide maximum power to the turbine in order to produce a higher output, and thus compressor degradation should be avoided.
Conventional turbine systems, in some cases, provide filters in an attempt to prevent fouling from entering the system, namely the compressor. In other cases, air is fed directly into the compressor without filtering. However, in either case, contaminates are passed into the system and eventually, the compressor is fouled by the contamination. As previously discussed, the result of the compressor fouling is a significant loss in performance and a significant increase in fuel consumption. Therefore, it is desirable to avoid such consequences.
As it will be recognized by one of ordinary skill in the art, maintaining gas turbine performance is an important consideration and therefore the removal of the compressor fouling is a standard best practice to regain any lost performance. Typically, the removal of fouling requires the use of compressor washing to maintain compressor efficiency. If compressor fouling is not addressed, compressor efficiency may decrease and as a result, system output will decrease, while fuel consumption will increase. A conventional means for removing fouling is to wash the particles that have already adhered system. In practice, washing the gas turbine is performed by injecting a wash solution upstream of the compressor inlet. By allowing the gas turbine rotor to rotate during wash, the solution is forced through the compressor and exits at the rear of the gas turbine. The solution may include water, various chemical agents, detergents, solvents, or any combination thereof.
However, fouling does not have a defined composition and typically any number of factors may influence its composition. For example, types of contaminates and quantities of contaminates may vary from location to location; one location may have a higher concentration of a certain contaminate, whereas a different location may have a lower concentration of that contaminate. Additionally, different locations may have completely different contaminates from another location. Furthermore, contamination may have a seasonal variation due to such things as local vegetation, industrial process, prevailing weather, or other ambient factors. Fouling can include generally any combination of contaminates and consequently, the various compositions of fouling are almost endless. As a result, washing procedures must also vary to cope with the variation in contaminates.
Accordingly, there is a need for a system and method for sampling and analysis of fouling composition such that washing may be optimized to cope with the varying compositions of fouling. Furthermore, there is a need for a system and method for continuous assessment of the ambient conditions, turbine parameters, turbine performance, and namely, the affect of the optimized washing on performance of the turbine. Application of an optimized wash process and such system and ambient condition assessment can ascertain the fullest recovery due to fouling and furthermore, identify other causes for performance degradation, thus, providing a means for optimized overall performance and fuel utilization.